Resolve "Refactor how PNDs are implemented in the code"

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Closes #243

controller/interfaces/networkdomain/pnd.go

@@ -41,7 +41,7 @@ type NetworkDomain interface {
 
 // LoadedPnd represents a PND that was loaded.
 type LoadedPnd struct {
-	ID          string `json:"_id" bson:"_id"`
+	ID          string `json:"id" bson:"id"`
 	Name        string `json:"name,omitempty"`
 	Description string `json:"description,omitempty"`
 }